The present disclosure, in some aspects, relates to a connecting structure for a fuel assembly (e.g. patent RU No. 2412492 of Nov. 12, 2008, G21C3/33). A connecting structure of a fuel assembly may include: a locking bush having a projecting section formed at the upper end portion of the bush; a top nozzle having a mounting opening into which the upper end portion of the locking bush is inserted; and the lock key which is installed inside the locking bush installation opening, which has a portion of the opening formed on the bottom surface of the key. The portion of the opening may have a shape corresponding to the projection section.
In view of the technical features of the present disclosure, the closest analog is the fuel assembly and device for mounting and removal of the top nozzle disclosed in patent RU No. 2075118 of 30.06.1992 G21C3/32, G21C19/00, which is chosen as a prototype.